Australia needs clean nuclear energy

It is now conventional wisdom that

• Combatting climate change calls for deep cuts in carbon dioxide (CO₂) emissions from using fossil fuels coal, oil and natural gas.
• A shift to "clean energy", specifically to renewables, will solve the emissions problem.
• Solar and wind will become the main renewable energy sources.

Even though emissions keep rising, public policy takes for granted that the renewables remedy for CO₂ emissions will eventually work. It's just a matter of persevering until "100% renewables" is reached. Problem solved. But is it? Here I try to quantify future clean energy requirements and check the progress being made. What emerges is a wake-up call.

1. What is "clean energy"?

Electricity was once seen as the shining example of clean energy. Yes, it was clean for users. Distant power stations did emit smoke and soot but only nearby populations suffered. The picture changed with realisation that CO₂ emissions had a global impact. Location was not relevant, quantity was. Lots of CO₂, anywhere, meant "dirty".

First, a quick look at measuring energy and emissions. Energy, the capacity to do work, is a quantity, an amount. Power is different from energy. Power is a rate. A simple analogy is that energy is to power as distance is to speed. (Colloquial usage of "power" for "energy" in terms like "power supply", "power station", "wind power" is a slight nuisance, safely ignored.)

The basic energy unit is the joule (J). The basic power unit is the watt (W). One watt = one joule per second. One sees joules and watts in everyday life, e.g. kilojoules measuring food energy, kilowatts rating the power of a toaster or car motor.

Measuring the energy a country uses calls for much bigger units. The most practical (in my view) are multiples of the joule. The petajoule PJ is 10¹⁵ joules, the exajoule EJ is 10¹⁸ joules. One strikes many different units in the energy field. Online tools like http://www.onlineconversion.com/energy.htm make comparisons easy.

The life-cycle CO₂ emissions intensity, the quantity of CO₂ emitted per unit of electrical energy, is themeasure of how clean the electricity from a given source is. It takes into account all production steps, like fuel and materials extraction; manufacture, transport and installation of energy conversion equipment; plant operation over its entire lifetime; and eventual end-of-life decommissioning and disposal. A solar panel, for example, emits no CO₂. It still results in emissions because its life cycle uses fossil fuels. Methodology for calculating life-cycle emissions intensities is complex but well established.

This Table shows typical values for various energy sources and technologies (from Intergovernmental Panel on Climate Change).

Typical life-cycle emissions intensities for electricity from different energy sources (kg CO₂/MWh)

No present technology has zero life-cycle emissions. There isn't a set standard for "clean electricity". However technologies that cut emissions by say 95% compared with coal should be considered clean. Accordingly, any below about 40 kg CO₂/MWhwould qualify.

The present major clean sources are hydro, solar, wind (all called renewables) and nuclear. Nuclear is declining in popularity and the growth potential of hydroelectricity is usually considered low because of environmental objections to large new dams. Solar and wind stand out as the popular leaders for meeting future growth in clean electricity.

Other renewables like biomass, geothermal, wave and tidal energy have their advocates. Also, some fossil fuel technologies under development (carbon capture and storage) reduce emissions using additional process steps to isolate and store much of the CO₂ produced. Opinions differ on their merits. I doubt whether any will reach the practical scale needed.

2. How much clean energy will be needed?

As most low-emissions energy comes in the form of electricity, aclean-energy world will essentially be an all-electric world running on low-CO₂ emissions electricity. Climate policies aim to displace all fossil fuels. How much clean electricity will that need?

Energy policy goals are commonly set in terms of renewable energy targets rather than fossil fuel abatement. For example, all but one Australian state and over half the states in the USA have legislated renewable portfolio goals. Victoria's target is 40% by 2025, Queensland's 50% by 2030, and ACT's 100% by 2020. Ultimate success occurs when 100% of the electricity comes from renewables. Hence the common slogan "100% renewables".

But there's a catch. Historically only around 40% of total fossil fuel energy is fed into electricity generation. So "100% renewables" does not equate to elimination of fossil fuels.

Where does the other 60% go? How will it be replaced? Here are some data, from the USA.

• Coal: 90% is burnt for electric power generation.
• Natural gas: 35% is used in the electricity industry. 34% goes to other industries. 17% goes to residential use and 12% to commercial use, mostly for heating buildings and water, for cooking and drying, and for refrigeration and cooling.
• Crude oil: 1% is used in power generation. Most is refined into petroleum products for a wide range of final uses. 69% of those products (petrol, diesel etc.) go to transportation and 25% to industrial applications such as petrochemical feedstocks, petroleum coke, asphalt and lubricants.

Some of these applications are based on fossil fuels' energy content and some on the rich chemical constitution, several thousand organic compounds, mainly hydrocarbons. For others that binary distinction isn't as straightforward.

Energy-based applications should be amenable to replacement by electrical energy from any source; heating and transport are the obvious candidates. Electric passenger cars are already well established; heavy transport, construction equipment, aviation and shipping less so. For others, the path to electrification is less clear. For example, elimination of fossil fuels in metal smelting, fertiliser manufacturing, petrochemicals, plastics, other non-metallic materials, and explosives will rely on quite new technologies. The amount of electrical or heat energy they will use is presently unknown. It isn't factored into standard long term energy projections like the International Energy Outlook (US Energy Information Administration), World Energy Outlook (International Energy Agency), or Integrated System Plan of Australia's national electricity market operator AEMO. However there are some pointers for future clean electricity needs and these can be related to present electricity supplies.

In 2018 electricity consumption was 941 PJ in Australia and95.8 EJ in the world.

• Based on 40% of fossil fuels going into electricity generation, one can simply multiply these totals by 2.5 to get a sensible minimum for future electricity.
• Prof MZ Jacobson (Stanford University) in his "100% WWS Project" developed roadmaps for infrastructures of 139 countries to be powered entirely by wind, water, and sunlight. In total, Jacobson's electrical energy inputs for 2050 came to about 380 EJ. That's about four times the 2018 global figure.
• In his book Sustainable Energy – without the hot air, the late Prof DJC MacKay (Cambridge University) estimated the 2050 energy needs of a fully electrified UK. With addition of only transportation and heating his result was nearly triple the present UK electricity supply.
• Prof BW Brook (University of Tasmania) arrived (in 2012) at a multiplier of 3.6 for the increase in global electrical energy needs from 2010 to 2060.

To summarise, there's no possibility that "100% renewables" will allow any economy to dispense with fossil fuels. At the very least, 2.5 times present electricity supply will be needed and multipliers in the range 3 to 4 look credible.

Let's take 3.5 as a reasonable estimate. That would mean that for eliminating fossil fuels by 2050 Australia would require around 3300 PJ (electrical) and the world 335 EJ (electrical).

These projections of future clean energy needs are rough but crucial. They need refining. In my view an industry-driven audit of every major industry and supply chain is required. There are always plenty of ideas. Identifying practical routes and solutions needs knowledge and experience.

3. Clean energy progress – the reality.

I have shown that a 100% renewables target that refers only to replacing today's electrical energy consumption falls far short of meeting future needs without fossil fuels. Lower targets mean exaggerated perceptions of progress in the clean energy transition. True progress can only be measured in relation to an electrical energy target that displaces all fossil fuels. For Australia that target is 3300 PJ (electrical).

The Table below relates this target to the latest full-year (2018) renewable energy data for Australia (from BP 2019 Statistical Review of World Energy).

2018 Australian renewable energy data
Electrical output by source and relative to a 2050 target of 3,300 PJ

Solar and wind, the main future clean growth prospects, in 2018 represented just 3.1% of Australia's 2050 requirements. Their combined output would need to increase 32-fold to meet the target. The global picture is similar; world solar output was 2.10 EJ, wind output 4.57 EJ, which are respectively 0.6% and 1.4% of a 335 EJ clean electrical energy target. Clearly there's a long way to go before anywhere near sufficient clean electricity is produced.

There is also a major quality problem. Solar and wind electricity are intrinsically intermittent. Without energy storage they cannot supply electricity meeting the normal expectation of availability on demand. For some reason there's a popular perception that one or more of the many possible energy storage solutions such as pumped hydroelectricity, electrochemical batteries and chemical storage like hydrogen or ammonia will prove to be practical at the required scale. This view is entirely speculative. Underlying concepts are old, the technologies have been maturing for centuries. The barrier is the massive scale needed. No storage technology is in large scale commercial operation with solar- and wind-based power supplies. Fossil fuels presently plug the gaps.

Speculation on storage prospects should carry no weight in public policy formulation at least until there is full scale demonstration of storage in real renewables-based grids.

4. Where to next?

Misunderstanding and/or misrepresenting future clean energy needs have led to overestimating prospects of renewable energy displacing fossil fuels. Today's popular choices for clean energy expansion, solar and wind, will struggle and in my view fail to reach the scale and quality required. All signs are that the less popular choice, nuclear power, will need to be reconsidered.

Nuclear energy has one of the lowest life-cycle emissions. Some 450 nuclear power stations now operate in 31 countries. It is barred in Australia and unpopular elsewhere to various degrees. Yet clean nuclear energy offers the required scale and quality to replace power stations that use fossil fuels. There are many thousands of those power stations in the world now. Many more thousands of clean nuclear power stations would be needed to eliminate fossil fuels. Even then, many innovative technologies would be required by a society based entirely on electrical and heat energy. The pathway will not be simple.

It also requires overcoming one very large barrier – public opinion. Can attitudes shift? I think increasing faith in solar and wind for a clean energy future has been working to strengthen opposition to nuclear. That faith, as shown here, is based on exaggerated claims for the performance of renewables and their ability to meet all future needs. If doubts grow, as they should, the faith will falter and attitudes to nuclear will change. In particular, historic Australian fears of nuclear as well as the more recent "too slow, too expensive" objections will slowly crumble. Nuclear energy will be welcomed as a necessity, not an option.